The reported mountain-lion attack in Foothills Park Saturday was deemed "unsubstantiated" by clearly skeptical state investigators Monday.
Police Chief Lynne Johnson told the City Council Monday night that officers believe the report of the attack is a fabrication.
After spending hours combing the trail, forensically checking the hiker's clothing and interviewing the purported victim, officials found no evidence to confirm the attack, game warden Patrick Foy of the Department of Fish and Game told the Weekly.
Foothills Park, where the reported incident occurred, and Arastradero Preserve, where a mountain-lion sighting was reported Saturday afternoon, may be re-opened soon, Palo Alto police Agent Dan Ryan said Monday afternoon.
The incident was "more of a wild-goose chase than we thought. We just can't confirm or deny it," he said.
The Portola Valley man who reported the attack -- which would have been the first lion attack on a human in Palo Alto history -- was hiking on the Los Trancos Trail in Foothills Park about 4 p.m. Saturday when he said he felt a sudden shove at his shoulder-blade level and tumbled down a hillside, stopping when he hit the trunk of a tree, according to Ryan.
He said he saw a lion continue to tumble down the hill, splash through Los Trancos Creek and scramble away, Ryan said.
But an aggressive, three-part investigation turned up nothing to substantiate the account, Foy said.
Four state game wardens and a professional wildlife tracker from the U.S. Department of Agriculture searched inside the park late into Sunday night and again Monday and found no trace, he said. They even tied sticks to the side of a truck, combing the ground near the incident to smooth out dirt so tracks would be obvious.
Hounds specially trained to detect mountain lions were brought to the shady trail but couldn't find a scent, he said.
The victim's shirt was sent to a lab to detect puncture marks, hair or saliva but nothing was found, he said.
"You'd be surprised how many hairs end up on that victim's back when a lion does attack them," he said.
The shirt had a couple small spots of blood believed to be the hiker's, Foy added. The hiker was badly scraped all over his body after the fall, including on his exposed legs from wearing shorts, Foy said.
Earlier Monday, authorities said they had no reason to doubt the hiker's account.
The hiker, who asked police not to disclose his identity, described a four-foot animal with a nearly four-foot tail, a description that matches lions rather than smaller bobcats, which are often mistakenly called lions despite having short tails, Foy said.
A lion was also reported sighted from a distance near the lake at Pearson-Arastradero Preserve on Saturday afternoon, about two miles away from the alleged attack, Ryan said.
And Foy and Ryan initially attributed the trouble finding a scent to the time delay between the reported attack and its reporting.
Ryan said the hiker only called officials Sunday afternoon, nearly a day later after the time of the reported attack. The hiker said he feared he'd be fined for using a Palo Alto park not open to non-residents, according to Ryan.
The man entered the preserve through an unofficial trail winding by houses in a residential neighborhood of Los Trancos Woods near the 100 block of Ramona Road.
Foothills Park has been closed to non-Palo Alto residents since the 1,400-acre preserve opened in 1959.
Despite the lack of evidence of a weekend attack, Foy cautioned against complacency. Because of its large deer population, the park is mountain lion habitat and visitors should know how to defend themselves, he said.
Children should be kept nearby and dogs should be leashed, he advised. If confronted, people should stand tall and shout aggressively or blow a whistle to scare the animal away, he said.
And if attacked, fight back, Foy added.